(Box 1) Figure I. Extracellular vesicle (EV) subtypes.

EVs are classified on the basis of their biogenesis and origin. Apoptotic bodies (50–5000 nm) arise when cells undergo apoptosis, typically containing nuclear fragments and cell organelles. Microvesicles (otherwise known as ectosomes or microparticles; 50–1000 nm) are shed via outward budding and fission of the plasma membrane. Exosomes (30–150 nm) are generated within the endosomal network and are released via exocytosis when a multivesicular body (MVB) fuses with the plasma membrane.